Electrostatic reproduction apparatus with photoconductive means to control the applied voltage at the copy sheet surface



Nov. 2, 1965 J. T. MONANEY 3,215,833

ELECTROSTATIC REPRODUCTION APPARATUS WITH PHOTOCONDUCTIVE MEANS TO CONTROL THE APPLIED VOLTAGE AT ,THE COPY SHEET SURFACE Filed Dec. 17, 1962 INVENTOR.

MQC

United States Patent ELECTROSTATIC REPRODUCTION APPARATUS WITH PHOTOCONDUCTIVE MEANS T0 CON- TROL THE APPLIED VOLTAGE AT THE COPY SHEET SURFACE Joseph T. McNaney, 8548 Boulder Drive, La Mesa, Calif.

Filed Dec. 17, 1962, Ser. No. 245,038 7 Claims. (Cl. 250-49.5)

This invention relates to a copy duplicating machine designed to print information on a sheet of copy material under the control of printed information appearing on an original copy.

The invention relates more particularly to an improvement in copy duplicating machines involving the use of radiation-to-electron converter means wherein a printing material, such as carbon, lampblack, or like materials, is made to attach itself to the copy material as a function of the opaque print areas on the original and simultaneously with the detection of these areas by the converter means.

In the invention the opaque print areas appearing on the original prevents the passage of radiation to a layer of radiation sensitive material to provide the generation of electrostatic flux necessary to effect the attachment of the printing material to the copy material.

It is an object of this invention to provide an improved copy duplicating machine capable of rendering extremely sharp copies of originals.

It is another object of this invention to provide a copy duplicating machine which is extremely simple, compact, positive in operation, and trouble-free in continued use.

It is still another object of this invention to provide a more effective means of creating an electrostatic latent image while simultaneously effecting a visual development thereof.

A further object of this invention is to utilize the flux being generated by the radiation-to-electron converter means to do both the creating of an electrostatic latent image on the copy material and the attraction of printing material thereto.

Other objects and advantages will appear hereinafter as a description of the invention proceeds.

The novel features that are considered characteristic of this improvement in copy duplicating machines are set forth with particularity in the appended claims. The invention itself, both as to its organization and method of operation, as well as additional objects and advantages, will best be understood from the following description when read in combination with the accompanying drawing in which:

FIGURE 1 is a diagrammatic illustration of an embodiment of the invention which will be designed to be sensitive to radiant energy involving the visible spectrum; and

FIGURE 2 shows a detail of a jacketed light conductor being utilized in the invention.

Referring now to FIGURE 1, and also to FIGURE 2 to the extent that it is a part of the invention, a radiationto-electron converter means 11 is shown as being supported in a bonding material 12. The converter means 11 includes a light conductor means 17, which can be in the form of an optical fiber 17 shown in FIGURE 2, jacketed by a light reflector means 18, and a layer 14 of photoconductor material intimately joined with a second end 16 surface of the converter means 11. The layer 14 has a first terminal 20 and a second terminal 22. The

3,215,833 Patented Nov. 2, 1965 material of layer 14 will be selected from a number of well known solids, such as lead selenide, lead sulfide, zinc sulfide, cadmium sulphide, selenium, germanium, silicon, or combinations of such materials, either in their pure state or in a modified state. The light conductor means 17 will take the form of an optical fiber 17 having an index of refraction of a predetermined amount and jacketed with a light conducting material 18 having an index of refraction less than the predetermined index of the fiber 17. The fiber 17 will be of a flint glass and jacketed in a crown glass. To meet the requirements of the invention the fiber 17 and the jacket 18 may, of course, be selected from any other suitable materials.

In the process of fabricating such an assembly of materials, the fiber 17 and the jacket 18 are drawn together in order to provide an extremely important fire-polished, contamination-free, interface between the two different materials at and along the juncture. The jacket 18 and its relation to the fiber 17 permits the jacket to function as an extremely efiicient radiant energy reflector in the system of conducting such energy upon entering an aperture 28 in a light mask 31 adjacent the one end of the converter 11 to the other end 16. The fiber 17 and the jacket 18 assembly, as illustrated in FIGURE 2, may have a cross sectional dimension whereby the length 24 will be greater than the width 26. The length 24 may be, for example, 0.010" and the width 26 may be as small as 0.001". The small width dimension 26 is important to the invention in that it will permit relatively large numbers of the converter means 11 to be placed and supported side-by-side in a very small space. The length 24 will be utilized in supporting the layer 14 of photoconductor material adjacent the second end of the converter means 11.

It is an object of the invention to support from 500 to 1,000 converter means 11 to the inch, extending from one side of the sheet of copy material to the other. This capability, of course, insofar as the data duplicating resolution requirements is concerned will be a contributing factor. From the standpoint of achieving good data duplicating resolution, the relatively large length dimension 24 of the converter means 11 will be effectively reduced by means of a radiation limiting aperture 28 of a radiation mask 30 adjacent the first end 32 surface of the converter means 10. The width of the aperture 28 will be as small as 0.001", extending from one end of the array of converter means 10 to the other.

A source 41 of light will be directed onto the surface of an original copy 35, having areas thereon to represent opaque print areas 37. The original 35 will be adjacent an aperture 28 of a light mask 31, and movable in the direction of the arrow 39. The opaque print areas 37 on the original 35 will prevent the passage of light from the source 41 to the layer 14 of photoconductor material. A sheet of copy material 40, having a first surface 42 and a second surface 44, is supported adjacent the second terminal 22 of the layer 14. The sheet 40 is movable in the direction of the arrow 46. A source of printing material is positioned adjacent the first surface 42 of the sheet 40, whereby the printing material 50 will be extended upward and applied to the first surface 42, by a material 50 circulating means 52.

In order to provide a copy of the opaque area-s 37 in the form of opaque areas 51 on the sheet 40, a prevention of the passage of radiation through the aperture 28 by the opaque areas 37 will result in the generation of a positive voltage flux from the converter means 11. The

latter, therefore, is provided with an additional element 60, having a first terminal 62 and a second terminal 64, and the second terminal being operatively connected to the second terminal 22 of the layer 14. The element 60 is an electrical conductor means 60, presenting a predetermined electrical resistance between the first terminal 62 and the second terminal 64.

An electrostatic flux generator means 54 is positioned adjacent the first surface 42 of the sheet 40 for the purpose of establishing thereon a uniform electrostatic charge, and upon which the sheet 40 will be moved to the position whereby it will be adjacent the second terminal 64 of the element 60. The first terminal of the element 60 is connected to the positive polarity of a source 49 of voltage. The first terminal 20 of the layer 14, the fluxgenerator 54, and the source 47 of printing material 50 is connected to the negative polarity of the voltage source 49.

When in operation, the flux generator 54 will subject the surface 42 of the sheet 40 to a negatively charged condition whereby a negatively charged printing material 50 will be unable to attach itself to the surface 42 of the sheet 40 when applied thereto. When light from the source 41 is prevented passage to the converter means 11 through the aperture 28 by means of the opaque areas 37 on the original 35, the influence of the voltage on the first terminal 62, which is capable of being extended to the second terminal 64, will allow an electrostatic flux to be generated from the second terminal 64 of the element 60. However, when light enters the aperture 28 through transparent areas 66 of the original 35, the light is conducted through the fiber 17 and reflected to the layer 14 by the jacket 18 of the converter means 11, allowing the negative potential on the first terminal 20 to be extended to the second terminal thereof and to the second terminal 64 of the element 60. The photoconductor layer 14 performs the function of a switch means in connecting the second terminal 64 to the negative polarity of the voltagesource 49.

The converter means 11 utilizes a plurality of elements 60, or, one element 60 for each light conductor fiber 17 in the array, allowing each element 60 to have an area dimension of 0.001" square at its second terminal 64 which is in contact with the second surface 44 of the sheet 40. The sheet 40 need not be of a thickness any greater than 0.002", allowing the printing material 50 to be not much more than this thickness dimension away from the terminal 64.

The object of the flux generated from the second terminal 64 of the element 60, in the direction of the negatively charged printing material 50, is to hold a predetermined amount of this material in a position adjacent the sheet 40 so that such printing material can attach itself thereto. In the process, the negatively charged surface 42 within a limited area will be sufficiently neutralized so that the printing material 50 may attach itself to the sheet 40. The sufficiently neutralized condition of the surface 42 to which I refer would, by itself, not be strong enough to attract and hold in position the predetermined amount of printing material so that this material can attach itself to the surface 42. Without the aid of the flux from the terminal 64 the desired printing effects would not be achieved. The surface 42 could, of course, be made sufiiciently positive to attract and hold in position the printing material for printing purposes, but this method presents problems which the present invention is designed to overcome. For example, under a set of conditions whereby the charge on the surface 42 is first made positive and then exposed to and permitted to receive printing material 50, the positive potential charge on the surface 42 would be required to generate a flux of the strength necessary to attract and hold in position the predetermined amount of printing material 50 so that this material can attach itself to the copy material. The

flux being generated from the terminal 64 for the purpose of establishing such a positive charge would be re quired to be many times greater than that which is needed in light of the present invention. Such flux requirements would also result in a much greater divergement of the flux, extending well beyond the 0.001 square terminal 64 area of the layer 60. This effect would, of course, defeat the object and advantage of the present invention in providing sharp copies of an original copy of information. Therefore, the concept of this invention, which includes the utilization of the flux being generated by the terminal 64 to simultaneously neutralize the charge on the surface 42 and effect the attachment of printing material to the surface 42, embodies the advantages hereinbefore set forth.

It should, of course, be understood that many of the other embodiments embracing the general principles and constructions hereinbefore set forth may be utilized and still be within the ambit of the present invention.

The embodiment, .as illustrated in FIGURE 1 for example, is not to be limited to the passage of light from the source 41 through the transparent areas 66 of the original 35, since it will be apparent to those skilled in the arts that the source of light 41 can be directed at the opposite surface of the original and a reflection of the light can be used to derive a copy therefrom. The opaque areas 37 will not reflect light through the aperture 28 and, therefore, the concept of printing hereinbefore set forth will remain the same.

The particular embodiment-s of the invention illustrated and described herein are illustrative only, and the invention includes such other modifications and equivalents as may readily appear to those skilled in the arts and within the scope of the appended claims.

I claim:

1. In a duplicating machine designed to print information on a sheet of copy material under the control of printed information appearing on an original including (a) a layer of photoconductor material having first and sec-0nd terminals;

(b) light conductor means having a predetermined index of refraction for supporting said layer and conducting light to said layer;

'(c) light reflector means jacketing said light conductor means having an index of refraction less than said predetermined index for controlling the reflection of light through said light conductor means and reflection of light to said layer;

(d) said copy material having first and second surfaces and said second surface being adjacent the second terminal of said layer and movable in relation thereto;

(e) said original being adapted to control the admittance of light to said light conductor means as a function of the printed information thereon and the position of said printed information in relation to said light conductor means;

the improvement comprising (-f) a source of printing material and means for bringing said printing material in contact with the first surface of said copy material directly opposite the second terminal of said layer;

(g) means for uniformly electrostatically charging the first surface of said copy material to preclude the attachment of said printing material to said first surface;

(h) electrical conductor means having first and second terminals and a predetermined electrical resistance therebetween, and said second terminal thereof being operatively connected to the second terminal of said layer and adjacent the second surface of said copy material;

(i) means for present-ing the influence of an electrical potential between said second terminal of the elecv v trical conductor means and the printing material for allowing the attachment of said printing material to the first surface of said copy material; and

(j) means for extending a potential neutralizing influence from the first terminal of said layer to said second terminal of the electrical conductor means upon the reflection of light to said layer to thereby prevent the attachment of printing material to said first surface of said copy material.

2. The invention as set forth in claim 1 wherein the improvement addition-ally includes (k) said influence of electrical potential being presented as a function of printed information on said original immediately adjacent said light conductor means and preventing the admittance of light to said light conductor means.

3. The invention as set forth in claim 1 wherein the improvement additionally includes (k) said layer being adapted to receive reflection of light as a function of light received from said original for controlling the generation of an electrostatic flux counter to the printer material repelling charge on the first surface of said copy material.

4. The invention as set forth forth in claim 1 wherein the improvement additionally includes (k) said light conductor means having an end and aperture means adjacent thereto; and

(I) said attachment of printing material tosaid first surface of the copy material occurring simultaneously with the positioning of the printed information on said original adjacent said aperture means and the preventing of the admittance of light to said light conductor means.

5. Means for utilization in a duplicating machine designed to print information on a copy sheet under the control of information appearing on an original sheet comprising:

(a) a source of light and means for exposing said original sheet to light therefrom;

(b) said copy sheet presenting first and second surfaces;

(c) a source of voltage having first and second terminals;

(d) a first electrode mean-s adjacent said first surface and connected electrically with said first terminal; (e) said first electrode means including a source of printing material;

(f) a second electrode means adjacent said second surface directly opposite said first electrode means; (g) said second electrode means including a layer of phot-oconductor material having first and second terminals, and an electrical conductor having first and second terminals and a predetermined electrical resistance therebetween, the second terminal of said layer being connected electrically with said conductor adjacent the second terminal thereof;

(h) the first terminal of said layer being connected electrically with the first terminal of said source of voltage, and the first terminal of said conductor .being connected electrically with the second terminal I of said source of voltage;

(i) optical fiber means for supporting said layer and for controlling the reflection of light to said layer upon the admittance of light thereto from said original sheet;

(j) said voltage being extended through said second electrode means to said second surface, in the absence of said reflection of light to said layer, and through said first electrode means to said first surface for all-owing the attachment of said printing material to the first surface of said copy material; and

(k) means for extending a voltage neutralizing influence from the first terminal of said layer to the second terminal of said electrical conductor upon the reflection of light to said layer to thereby prevent the attachment of printing material to said first surface of said copy material.

6. Means for utilization in a duplicating machine designed to print information on a copy sheet under the control of information appearing on an original sheet comprising:

(a) a source of light and means for exposing said original sheet to light therefrom;

(b) said copy sheet presenting first and second surfaces;

(c) a source of voltage having first and second terminals;

(d) first electrode means, including a source of printing material, adjacent said first surface and connected electrically with said first terminal;

(e) second electrode means adjacent said second surface directly opposite said printing material including an electrical conductor having first and second terminals and a predetermined electrical resistance there-between, and the first terminal thereof being connected electrically with the second terminal of said source of voltage;

(f) a layer of photo-conductor material having first and second terminals, the second terminal of said material being connected electrically with said electrical conductor adjacent the second terminal thereof;

(g) means for presenting the influence of said voltage across said copy sheet between said first electrode means and the second terminal of said electrical conductor for allowing the attachment of said printing material to the first surface of said copy material;

(-h) optical fiber means for supporting said photoconductor material and for controlling the reflection of light thereto from said original sheet; and

(i) means for extending a voltage neutralizing infiuence from the first terminal of said layer to said second terminal of the electrical conductor upon the reflection of light to said layer to thereby prevent the attachment of printing material .to said first surface.

7. Means for utilization in a duplicating machine designed to print information on a copy sheet under the control of information appearing on an original sheet comprising:

(a) a source of light and means for exposing said original sheet to light therefrom;

(b) said copy sheet presenting first and second surfaces;

(c) a source of voltage having first and second terminals;

(d) first electrode means, including a source of printing material, adjacent said first surface and connected electrically with said first terminal;

(e) second electrode means adjacent said second surface directly opposite said printing material having first and second terminals and a predetermined electrical resistance therebetween, and the first terminal thereof being connected electrically with the second terminal of said source of voltage;

(f) a photoconductor having first and second terminals, the second terminal of said photoconductor being connected electrically with the second terminal of said second electrode means;

(g) means for presenting the influence of said voltage across said copy sheet between said printing material and the second terminal of said second electrode means for allowing the attachment of said printing material to the first surface of said copy material;

(11) means for electrically coupling the first terminal of said photoconductor to said source of printing material and the first terminal of said voltage; and

(i) means for extending the voltage from said first voltage terminal to the second terminal of said 7 photoconduct-or upon the reflect-ion of light thereto, thereby decreasing the influence of said voltage across saidcopy sheet and to prevent the attachment of printing material to said first surface of said copy sheet.

References Cited by the Examiner UNITED STATES PATENTS 2,771,336 11/56 M'acGriff 25049.5 10

Haacke 250-495 Huebner 250-495 Gundlack 25049.5 Johnson 2 504 9.5 McNaney 25049.5 Childress et a1. 25049.5 'McNaney 250-495 RALPH G. NILSON, Primary Examiner. 

1. IN A DUPLICATING MACHINE DESIGNED TO PRINT INFORMATION ON A SHEET OF COPY MATERIAL UNDER THE CONTROL OF PRINTED INFORMATION APPEARING ON AN ORIGNIAL INCLUDING (A) A LAYER OF PHOTOCONDUCTOR MATERIAL HAVING FIRST AND SECOND TERMINALS; (B) LIGHT CONUCTOR MEANS HAVING A PREDETERMINED INDEX OF REFRACTION FOR SUPPORTING SAID LAYER AND CONDUCTING LIGHT TO SAID LAYER; (C) LIGHT REFLECTOR MEANS JACKETING SAID LIGHT CONDUCTOR MEANS HAVING AN INDEX OF REFRACTION LESS THAN SAID PREDETERMINED INDEX FOR CONTROLLING THE REFLECTION OF LIGHT THROUGH SAID LIGHT CONDUCTOR MEANS AND REFLECTION OF LIGHT TO SAID LAYER; (D) SAID COPY MATERIAL HAVING FIRST AND SECOND SURFACES AND SAID SECOND SURFACE BEING ADJACENT THE SECOND TERMINAL OF SAID LAYER AND MOVABLE IN RELATION THERETO; (E) SAID ORIGINAL BEING ADAPTED TO CONTROL THE ADMITTANCE OF LIGHT TO SAID LIGHT CONDUCTOR MEANS AS A FUNCTION OF THE PREINTED INFORMATION THEREON AND THE POSITION OF SAID PRINTED INFORMATION IN RELATION TO SAID LIGHT CONDUCTOR MEANS; THE IMPROVEMENT COMPRISIING (F) A SOURCE OF PRINTING MATERIAL AND MEANS FOR BRINGING SAID PRINTING MATERIAL IN CONTACT WITH THE FIRST SURFACE OF SAID COPY MATERIAL DIRECTLY OPPOSITE THE SECOND TERMINAL OF SAID LAYER; 